Sestze Mech Problem

Hello, I have long tryed to make a mech but recently i found the great player Sestzes mechs, I found one of his threads where he gave the code away (

I found this great but i encountered several problems with the legs and the E2, First off, i dont really understand Sestzes tutorial on legs, A quick and better tutorial would help. 2rd, The E2 allways say “Parts are missing” and i have no idea why.

Thank you for helping me! -Ze_Captain